目录
一、实验目的
二、实验环境
三、实验原理
四、实验任务
代码
一、实验目的
1. 理解MIPS处理器指令格式及功能。
2. 掌握lw, sw, beq, bne, lui, j, jal指令格式与功能。
3. 掌握ModelSim和ISE\Vivado工具软件。
4. 掌握基本的测试代码编写和FPGA开发板使用方法。
二、实验环境
1. 装有ModelSim和ISE\Vivado的计算机。
2. Sword\Basys3\EGo1实验系统。
三、实验原理
MIPS 32位处理器的指令格式分为R型、I型和J型。R型为寄存器型，即两个源操作数和目的操作数都是寄存器性。I型为操作数含有立即数。而J型特指转移类型指令，如图1所示。
如图2所示，本次实验将实现实验挑选剩余部分MIPS处理器指令进行实现。主要是部分R型和J型指令。指令的格式如图2所示，指令的功能参考资料1（李亚民. 计算机原理与设计：Verilog HDL版）。
如图3所示为按照单指令周期设计MIPS处理器内部结构。所有控制信号及字段均标注出来。另外，每条指令周期都包含2个clk，即PC模块用1个clk，Regfile和DataMem模块用1个clk，也可以说是由2个时钟构成的指令流水线。为了便于今后的扩展，将MIPS处理器进行了分阶段设计，这样结构更清晰，也有利于流水线的设计。随着后续指令的不断添加，处理器内部结构设计也会进行相应的调整，但时序部分应保持不变。
四、实验任务
1. 用Verilog HDL设计32位MIPS处理指令实现,参照图3的MIPS内部结构示意图，先编写基本实现代码，即能实现j和jal指令的取指令和执行指令，在Modelsim上仿真测试。
2. 参照图2，将设计的MIPS处理器改造为分阶段实现方案，注意每条指令周期平均只包含1个时钟周期。
3.编写指令存储测试文件，在Modelsim上调试通过。
代码
`define RstEnable 1'b1
`define RstDisable 1'b0
`define RomEnable 1'b1
`define RomDisable 1'b0
`define Zero 0
`define Valid 1'b1
`define Invalid 1'b0
//I
`define Inst_ori 6'b001101
`define Inst_addi 6'b001000
`define Inst_andi 6'b001100
`define Inst_xori 6'b001110
`define Inst_lui 6'b001111
`define Inst_subi 6'b001001
//R
`define Inst_r 6'b000000
`define Inst_add 6'b100000
`define Inst_sub 6'b100010
`define Inst_and 6'b100100
`define Inst_or 6'b100101
`define Inst_xor 6'b100110
`define Inst_sll 6'b000000
`define Inst_srl 6'b000010
`define Inst_sra 6'b000011
//J
`define Inst_j 6'b000010
`define Inst_jal 6'b000011
`define Inst_jr 6'b001000`define Inst_beq 6'b000100
`define Inst_bne 6'b000101`define Nop 6'b000000
`define Or 6'b000001
`define Add 6'b000010
`define And 6'b000011
`define Xor 6'b000100
`define Lui 6'b000101
`define Sub 6'b000110
`define Sll 6'b000111
`define Srl 6'b001000
`define Sra 6'b001001
`define J 6'b001010
`define Jal 6'b001011
`define Beq 6'b001100
`define Bne 6'b001101
`define Jr 6'b001110`include "define.v"
module EX(input wire rst,input wire [5:0] op, input wire [31:0] regaData,input wire [31:0] regbData,input wire regcWrite_i,input wire [4:0]regcAddr_i,output reg [31:0] regcData,output wire regcWrite,output wire [4:0] regcAddr
); always@(*)if(rst == `RstEnable)regcData = `Zero;elsebegincase(op)`Or:regcData = regaData | regbData;`Add:regcData = regaData + regbData;`And:regcData = regaData & regbData;`Xor:regcData = regaData ^ regbData;`Lui:regcData = regaData;/*`Lui:regcData = regaData | regbData;*/`Sub:regcData = regaData - regbData;`Sll:regcData = regbData << regaData;`Srl:regcData = regbData >> regaData;`Sra:regcData = ($signed(regbData)) >>> regaData;`J:regcData = `Zero;`Jr:regcData = `Zero;`Jal:regcData = regbData;`Beq:regcData = `Zero;`Bne:regcData = `Zero;default:regcData = `Zero;endcaseendassign regcWrite = regcWrite_i;assign regcAddr = regcAddr_i;
endmodule`include "define.v";
module ID (input wire rst, input wire [31:0] pc, //Jinput wire [31:0] inst,input wire [31:0] regaData_i,input wire [31:0] regbData_i,output reg [5:0] op, output reg [31:0] regaData,output reg [31:0] regbData,output reg regaRead,output reg regbRead,output reg regcWrite,output reg [4:0] regaAddr,output reg [4:0] regbAddr, output reg [4:0] regcAddr,output reg [31:0] jAddr, //Joutput reg jCe//J);wire [5:0] inst_op = inst[31:26]; reg [31:0] imm;//Rwire[5:0] func = inst[5:0]; //Jwire [31:0] npc = pc + 4;always@(*)if(rst == `RstEnable)beginop = `Nop; regaRead = `Invalid;regbRead = `Invalid;regcWrite = `Invalid;regaAddr = `Zero;regbAddr = `Zero;regcAddr = `Zero;imm = `Zero;jCe = `Invalid;//JjAddr = `Zero;//Jendelse beginjCe = `Invalid;//JjAddr = `Zero;//Jcase(inst_op)`Inst_ori:beginop = `Or; regaRead = `Valid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = `Zero;regcAddr = inst[20:16];imm = {16'h0, inst[15:0]};end`Inst_andi:beginop = `And; regaRead = `Valid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = `Zero;regcAddr = inst[20:16];imm = {16'h0, inst[15:0]};end`Inst_xori:beginop = `Xor; regaRead = `Valid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = `Zero;regcAddr = inst[20:16];imm = {16'h0, inst[15:0]};end`Inst_addi:beginop = `Add; regaRead = `Valid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = `Zero;regcAddr = inst[20:16];imm = {{16{inst[15]}}, inst[15:0]};end`Inst_subi:beginop = `Sub; regaRead = `Valid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = `Zero;regcAddr = inst[20:16];imm = {{16{inst[15]}}, inst[15:0]};end`Inst_lui:beginop = `Lui; regaRead = `Invalid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = `Zero;regbAddr = `Zero;regcAddr = inst[20:16];imm = {inst[15:0],16'h0};end`Inst_r:case(func)`Inst_add:beginop = `Add; regaRead = `Valid;regbRead = `Valid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = inst[15:11];imm = `Zero;end`Inst_or:beginop = `Or;regaRead = `Valid;regbRead = `Valid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = inst[15:11];imm = `Zero;end`Inst_sub:beginop = `Sub;regaRead = `Valid;regbRead = `Valid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = inst[15:11];imm = `Zero;end`Inst_and:beginop = `And;regaRead = `Valid;regbRead = `Valid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = inst[15:11];imm = `Zero;end`Inst_xor:beginop = `Xor;regaRead = `Valid;regbRead = `Valid;regcWrite = `Valid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = inst[15:11];imm = `Zero;end`Inst_sll:beginop = `Sll;regaRead = `Invalid;regbRead = `Valid;regcWrite = `Valid;regaAddr = `Zero;regbAddr = inst[20:16];regcAddr = inst[15:11];imm = {27'b0,inst[10:6]};end`Inst_srl:beginop = `Srl;regaRead = `Invalid;regbRead = `Valid;regcWrite = `Valid;regaAddr = `Zero;regbAddr = inst[20:16];regcAddr = inst[15:11];imm = {27'b0,inst[10:6]};end`Inst_sra:beginop = `Sra;regaRead = `Invalid;regbRead = `Valid;regcWrite = `Valid;regaAddr = `Zero;regbAddr = inst[20:16];regcAddr = inst[15:11];imm = {27'b0,inst[10:6]};end`Inst_jr:beginop = `Jr;regaRead = `Valid;//rsregbRead = `Invalid;regcWrite = `Invalid;regaAddr = inst[25:21];regbAddr = `Zero;regcAddr = `Zero;jAddr = regaData;jCe = `Valid;imm = `Zero;enddefault:beginregaRead = `Invalid;regbRead = `Invalid;regcWrite = `Invalid;regaAddr = `Zero;regbAddr = `Zero;regcAddr = `Zero;imm = `Zero;endendcase//J`Inst_j:beginop = `J;regaRead = `Invalid;regbRead = `Invalid;regcWrite = `Invalid;regaAddr = `Zero;regbAddr = `Zero;regcAddr = `Zero;jAddr = {npc[31:28], inst[25:0], 2'b00};jCe = `Valid;imm = `Zero;end `Inst_jal:beginop = `Jal;regaRead = `Invalid;regbRead = `Invalid;regcWrite = `Valid;regaAddr = `Zero;regbAddr = `Zero;regcAddr = 5'b11111;jAddr = {npc[31:28], inst[25:0], 2'b00};jCe = `Valid;imm = npc;end//J `Inst_beq:beginop = `Beq;regaRead = `Valid;regbRead = `Valid;regcWrite = `Invalid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = `Zero;jAddr = npc+{{14{inst[15]}},inst[15:0],2'b00};jCe=(regaData==regbData)?`Valid:`Invalid; /* if(regaData==regbData)jCe = `Valid;elsejCe = `Invalid;*/imm = `Zero;end `Inst_bne:beginop = `Bne;regaRead = `Valid;regbRead = `Valid;regcWrite = `Invalid;regaAddr = inst[25:21];regbAddr = inst[20:16];regcAddr = `Zero;jAddr = npc+{{14{inst[15]}},inst[15:0],2'b00};jCe=(regaData!=regbData)?`Valid:`Invalid; /* if(regaData!=regbData)jCe = `Valid;elsejCe = `Invalid;*/imm = `Zero;end default:beginop = `Nop; regaRead = `Invalid;regbRead = `Invalid;regcWrite = `Invalid;regaAddr = `Zero;regbAddr = `Zero;regcAddr = `Zero;imm = `Zero;endendcase endalways@(*)if(rst == `RstEnable)regaData = `Zero;else if(regaRead == `Valid)regaData = regaData_i;else regaData = imm;always@(*)if(rst == `RstEnable)regbData = `Zero; else if(regbRead == `Valid)regbData = regbData_i;elseregbData = imm; endmodule
`include "define.v"
module IF(input wire clk,input wire rst,input wire [31:0] jAddr,//Jinput wire jCe,//Joutput reg ce,
output reg [31:0] pc
);always@(*)if(rst == `RstEnable)ce = `RomDisable;elsece = `RomEnable;
/* always@(posedge clk)if(ce == `RomDisable)pc = `Zero;elsepc = pc + 4;
*/always@(posedge clk)if(ce == `RomDisable)pc = `Zero;else if(jCe == `Valid)//Jpc = jAddr;elsepc = pc + 4;
endmodule
`include "define.v"
module MIPS(input wire clk,input wire rst,input wire [31:0] instruction,output wire romCe,output wire [31:0] instAddr
);wire [31:0] regaData_regFile, regbData_regFile;wire [31:0] regaData_id, regbData_id; wire [31:0] regcData_ex;wire [5:0] op; wire regaRead, regbRead;wire [4:0] regaAddr, regbAddr;wire regcWrite_id, regcWrite_ex;wire [4:0] regcAddr_id, regcAddr_ex;//Jwire [31:0] jAddr;wire jCe;IF if0(.clk(clk),.rst(rst),.jAddr(jAddr),//J.jCe(jCe),//J.ce(romCe), .pc(instAddr));ID id0(.pc(instAddr),//J.jAddr(jAddr),//J.jCe(jCe),//J.rst(rst), .inst(instruction),.regaData_i(regaData_regFile),.regbData_i(regbData_regFile),.op(op),.regaData(regaData_id),.regbData(regbData_id),.regaRead(regaRead),.regbRead(regbRead),.regaAddr(regaAddr),.regbAddr(regbAddr),.regcWrite(regcWrite_id),.regcAddr(regcAddr_id));EX ex0(.rst(rst),.op(op), .regaData(regaData_id),.regbData(regbData_id),.regcWrite_i(regcWrite_id),.regcAddr_i(regcAddr_id),.regcData(regcData_ex),.regcWrite(regcWrite_ex),.regcAddr(regcAddr_ex)); RegFile regfile0(.clk(clk),.rst(rst),.we(regcWrite_ex),.waddr(regcAddr_ex),.wdata(regcData_ex),.regaRead(regaRead),.regbRead(regbRead),.regaAddr(regaAddr),.regbAddr(regbAddr),.regaData(regaData_regFile),.regbData(regbData_regFile));
endmodule`include "define.v"
module RegFile(input wire clk,input wire rst,input wire we,input wire [4:0] waddr,input wire [31:0] wdata,input wire regaRead,input wire regbRead,input wire [4:0] regaAddr,input wire [4:0] regbAddr,output reg [31:0] regaData,output reg [31:0] regbData
);reg [31:0] reg32 [31 : 0]; always@(*)if(rst == `RstEnable)regaData = `Zero;else if(regaAddr == `Zero)regaData = `Zero;elseregaData = reg32[regaAddr];always@(*)if(rst == `RstEnable) regbData = `Zero;else if(regbAddr == `Zero)regbData = `Zero;elseregbData = reg32[regbAddr];always@(posedge clk)if(rst != `RstEnable)if((we == `Valid) && (waddr != `Zero))reg32[waddr] = wdata;else ;
endmodulemodule SoC(input wire clk,input wire rst
);wire [31:0] instAddr;wire [31:0] instruction;wire romCe; MIPS mips0(.clk(clk),.rst(rst),.instruction(instruction),.instAddr(instAddr),.romCe(romCe)); InstMem instrom0(.ce(romCe),.addr(instAddr),.data(instruction));
endmodule`include "define.v"
module soc_tb;reg clk;reg rst;initialbeginclk = 0;rst = `RstEnable;#100rst = `RstDisable;#10000 $stop; endalways #10 clk = ~ clk;SoC soc0(.clk(clk), .rst(rst));
endmodule
